The clock is ticking for Georgia. She’s got about a week to live, and she needs to find a mate. How will she know when she’s found Mr. Right? By his flashing light. That’s because Georgia is a newly emerged firefly who was raised in captivity by researchers at Butterfly Pavilion, a zoo near Denver, Colorado. Now, in an insect-world version of The Dating Game—or The Bachelorette—she’ll be introduced to five potential suitors who just days before were living in a wetland about an hour north near Fort Collins.
On a warm June evening, a team from the zoo armed with nets and plastic collection cups, convene at a meadow filled with cattails, rushes, and willows and punctuated with the songs of red-winged blackbirds.
“We're going to see them start going pretty soon once the sun dims,” says Malaney Dodson, Butterfly Pavilion’s animal wellbeing coordinator who’s been caring for the fireflies in the lab. She’s preparing to collect a predetermined number of males and females, which will later be paired off in the hopes they’ll mate.
We’ve already seen a few fireflies, which are actually beetles with yellow and red coloration, just hanging out at the base of some grasses in the wetland. Dodson says, they’re resting up before for their “nuptial flight.”
As the sun starts to set, the show begins. A few blinks here, a few flashes there, increasing every minute. Some of you who live in Colorado might be as surprised as I was. There are fireflies here?
Yes, says Francisco Garcia Bulle, PhD, who is the director of research and conservation at Butterfly Pavilion. While most people associate fireflies with the East Coast or Midwest, there are populations from the Photuris genus found in Colorado.
Bulle says little is understood about fireflies generally, and especially about the three species in the state that overwinter deep underground, so Butterfly Pavilion started its Firefly Lifecyle Project in 2017 to learn more. What they do know is that fireflies are an indicator species, which would be the first animals to decline or die if an ecosystem changes or fragments. The creatures are sensitive to changes, so as goes the firefly, so goes the neighborhood and the other organisms that live there.
Threats to fireflies range from pesticide use to habitat loss—and unsurprisingly, light pollution, since the main reason fireflies glow is to attract a mate. It’s their communication channel, with females and males each having distinct flashing patterns that signal to one another that they’ll be a good fit. “You'll see it in the night,” Bulle says. “It's like this like big disco nightclub for them.”
Producing light is rare for terrestrial animals. Most bioluminescent organisms are found in the ocean. The fireflies produce an enzyme called luciferase to create the glow that emits from their lower abdomens. The flashing is not always pillow talk and romance though. They’ll also use their pulses of light to warn of danger—and some have treachery in mind. Bulle says some females will copy a pattern from a female of another species to attract boys from that species. “What happens? She eats them. She's getting that extra protein. She's femme fatale. She's tricking them and then boom, she takes them down.”
Gateway Insects
The intriguing behaviors of fireflies can only be learned by studying the insects over time. The week before they came out to collect specimens, Georgia, the female firefly back at Butterfly Pavilion waiting for her betrothed, emerged from her larval stage after three years at the zoo. Although she is only the fifth adult to pupate in their care, she’s already helping them learn more about Colorado’s fireflies.
The more they can understand the insect’s biology and lifestyle, the sooner they can reintroduce populations into the wild. For example, they will want to document what soil types, temperatures, and moisture levels fireflies need to pupate—which is the time they make a protective cell to go into metamorphosis. Fireflies need moisture, which could be harder to find in a changing climate, with more heat waves and droughts.
The team is also investigating what they like to eat. Apparently, apples are a favorite, as are snails and slugs. Don’t be fooled by larvae that are half the size of a grain of rice when they first hatch. They’re fierce predators, able to poison and eat animals several times their size, which in the wild helps keep ecosystems in balance by reducing potential pests. That’s just one benefit they provide to humans, so the team hopes that people, especially folks who might have phobias about bugs, will learn to appreciate them. Certainly, glowing like fairies helps to make them endearing.
“I call them a gateway insect, just like honeybees or butterflies,” Bulle says, adding that fireflies are a starting place for people who can then move on to love mosquitoes or cockroaches or other animals that might not be as charismatic.
Plan B
Fireflies live in many places around the globe, and not all flash. There are numerous species that emerge at different times in the U.S., depending on the regional climate. In warmer southern states like Florida and Texas, fireflies may begin emerging as early as April or May. In Arizona, sightings tend to peak during the monsoon season in July and August. Bulle has studied fireflies in the Ecuadorian Amazon, which he calls one of the most stunning conservation sites he’s ever seen.
Less than an hour after dark, Dodson has collected most of the fireflies she’ll bring back to the lab. She’s particularly stoked to find “the one” for Georgia. “Yeah, like, why'd you catch me,” she coos to a firefly she puts it in a plastic container. “Because I'm gonna get you a girlfriend,” she tries to reassure the flashing insect.
If all goes well from tonight’s work, two, maybe three years from now, several adults will emerge. Given that insects are declining at an alarming rate worldwide, the team says the worst-case scenario is that their research will preserve—in captivity—the firefly species found in Colorado. A more optimistic view would be that, one day, this wetland could be home to Georgia’s great-great-great-grandchildren, who will thrive because of the flashes of insight the research revealed.
This story was shared via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah, and New Mexico including Aspen Public Radio.
